正焦弦

例句：

1. 1. The engineer used a special tool to make the machine work more efficiently.
   工程师使用一种特殊的工具使机器更有效地工作。
2. 2. The scientist made an important discovery about the universe's structure.
   科学家发现了关于宇宙结构的重要发现。
3. 3. The musician played a beautiful piece of music that perfectly matched the mood of the event.
   音乐家演奏了一首美丽的音乐，完美地与活动的气氛相匹配。